The invention concerns a spoke connecting a wheel hub to an external ring of a spoked drive wheel.
In a known hydrodynamic torque converter, for example U.S. Pat. No. 3,101,011, operation with power splitting is only envision for the fluid coupling range. Namely, the second output shaft of the torque converter, driven by the pump wheel via the spoked drive wheel, only transmit a proportion of the drive power in the highest gear when the turbine wheel and the pump wheel have approximately the same rotational speed, allowance being made for the relative slip. The publication gives no further details of the spoke cross-section of the known spokes of the spoked drive wheel of this torque converter. It is only the representation in the drawing which suggests a circular shape which obviously makes allowance for the varying incident flow directions during the transition between the converter and fluid coupling ranges.
Starting from the fact that the spoke always represents a perturbation factor for the flow in the hydrodynamic working cycle, the object on which the invention is based consists essentially of designing a spoke for hydrodynamic torque converter in such a way that the loads due to the torque transmitted and the centrifugal forces can be kept as small as possible.
The object described is achieved, according to the invention, by providing the spokes to have a wing shaped cross sectional profile along a profile axis transverse to the axis of rotation of the wheel.
By including the profile main axis at an acute angle of incidence relative to a plane perpendicular to the axis of rotation, a minimum flow resistance is obtained over the wole of the rotational speed ratio of the converter.
By inclining the spoke axis between radially outer and inner ends at an acute sweep-back angle relative to the radius of the wheel, the loads arising from the torque transmission, on the one hand, and the centrifugal forces, on the other, are mutually balanced at the smallest possible flow losses.
The edge of the profile are tapered to keep the flow losses small.
The edges of the profile have a minimum width in order not to endanger handling during assembly because of excessive sharpness of the profile ends.
The perturbing influence, on the flow through the spoked drive wheel, is limited to a tolerable amount by limiting the number of spokes.
High strength and stiffness are achieved at the connecting points of the spoked drive wheel to the pump wheel of the torque converter by providing fastenting eyes in an external ring adjacent the end of the spoke.
Further objects, features, and advantages of the present invention will become more apparent from the following description when taken with the accompanying drawings which show, for purposes of illustration only, an embodiment in accordance with the present invention.